The study of biology and other natural sciences commonly involves microscopes and magnifying glasses to view small objects of interest. Relatively inexpensive microscopes are known for educational use by children. Some such devices may be used indoors and outdoors.
One hand-held magnifying device is described in U.S. Pat. No. 4,737,016. The '016 patent discloses a hand-held magnifying device having a small body that includes a fixed magnifying lens. A slidable adjusting tube is positioned near the lens for focusing. The adjusting tube is adapted to receive an object-supporting slide or panel (carrying an object of interest) so that the slide or panel is perpendicularly oriented to the adjusting tube. The end portion of the slide or panel, which may be formed to provide a transparent enclosure to hold an insect or the like, is positioned in alignment with the lens. By sliding the adjusting tube relative to the body of the device and in a direction parallel to the axis of view, the distance between the object and the lens is varied to bring the object into focus. The adjusting tube may be rotated about its axis to move the object being viewed from left to right within the field of view. The slide may be inserted more or less deeply into the adjusting tube to position the object relative to the lens in a rectilinear manner.
The device of the '016 patent has several drawbacks. First, the '016 viewer is difficult to use in that the plunger can easily be inadvertently pressed or moved while an object is being viewed, causing the object to move out of focus. Second, the object holder cannot be angled relative to the axis of view to permit the user to easily focus on part of the object that does not present itself "full-face" in front of the lens. Third, the object holder of the '016 device has to be moved in each direction separately when positioning an object in front of the lens, which does not allow for fluid, three-dimensional movement of the object mount. Because the '016 device requires considerable manual dexterity to focus and to manipulate the object holder, it is difficult for children to use, particularly when the object observed is a moving object.